Sleeve damper assembly

ABSTRACT

A damper for a linear element of a motor vehicle drivetrain such as a cable, a transmission oil fill tube or an engine oil dipstick tube constitutes a loose fitting sleeve or annulus disposed about the linear component. The damper may be positioned on a substantially vertical tube by a stop which may be any device such as a sleeve of material having an outside diameter larger than the inside diameter of the damper that is clamped or secured to the tube. Alternatively, the damper may be of sufficient length that one end may be clamped to the tube while the other end, which loosely fits on the tube, acts as a damper. The damper may be fabricated of a material such as closed cell foam or other relatively lightweight, resilient and compressible material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This divisional application claims the benefit of U.S. application Ser.No. 13/074,517 filed on Mar. 29, 2011. The entire contents of the aboveapplication are incorporated herein by reference.

FIELD

The present disclosure relates to damper assemblies and moreparticularly to sleeve damper assemblies for damping sympatheticvibrations in motor vehicle engine components.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

The impact of unwanted, sympathetic vibration or resonances of elementsin mechanical systems ranges from inconsequential, through annoying andservice life limiting to problematic and catastrophic. Certainly theextent or magnitude of such sympathetic vibration plays a role inlocating a particular activity along the foregoing spectrum.Additionally, the type of product, i.e., whether it is a refrigerator,an air compressor, an electric generator, a motor vehicle powertrain, anairplane or a suspension bridge determines whether the vibration is anuisance, the source of consumer complaints or a safety issue.

The most complex consumer products, at least from a mechanicalstandpoint, are clearly motor vehicles. With thousands of components,frequent new and re-designed mechanical components, an emphasis onweight reduction, lengthy service lives and vehicle service and careranging from virtually total neglect to careful and complete,sympathetic vibration or resonance of components is a constant andconstantly addressed engineering issue.

In motor vehicles, the drive or powertrain tends to be the situs of mostsympathetic vibration problems and thus the focus of the most attention.A common area of difficulty typically involves a linear component, suchas a cable or tubing, that extends unsupported between two points. Themost difficult problems arise when a linear element includes anunsupported length that is free standing, such as a transmission oilfill tube or engine oil dipstick tube.

Various solutions have been heretofore proposed. Perhaps the most commoninvolves strengthening the linear element. Such a solution adds to theweight and cost of the component and it still may be subject tosympathetic vibration or resonance—just at a different frequency. Addingadditional braces or points of attachment is also a common solution but,once again, it not only adds weight and cost but also increases the timeand cost of assembly.

The present invention is directed to reducing or eliminating sympatheticvibration of linear components in mechanical systems such as vehiclepowertrains.

SUMMARY

The present invention provides a damper assembly for a linear element ofa motor vehicle such as a cable, tube, transmission oil fill tube orengine oil dipstick tube. A first embodiment of the damper assemblyconstitutes a loose fitting sleeve or annulus disposed about a linearcomponent such as a cable, a cooler pipe or line, a transmission oilfill tube or engine dipstick tube. The sleeve damper assembly may bepositioned on a substantially vertical tube by a stop which may be anydevice such as a sleeve of material having an outside diameter largerthan the inside diameter of the damper that is clamped or secured to thetube. In a second embodiment, the damper sleeve is of sufficient lengththat one end may be clamped to the tube while the other end, whichloosely fits on the tube, acts as a damper. The damper sleeve may befabricated of a material such as closed cell foam or other relativelylightweight, resilient and compressible material. The damper moves or“rattles” in random, chaotic manner to absorb energy and interfere withand thus minimize or eliminate resonance or harmonic vibration of theassociated linear element.

Thus it is an aspect of the present invention to provide a damperassembly for a linear mechanical element such as a cable, a cooler pipeor line, a transmission fill tube or an engine dipstick tube.

It is a further aspect of the present invention to provide a dampersleeve which fits loosely about a linear mechanical element.

It is a still further aspect of the present invention to provide adamper sleeve having at least a portion which fits loosely about alinear mechanical element.

It is a still further aspect of the present invention to provide adamper assembly which moves or “rattles” in a random, chaotic manner.

It is a still further aspect of the present invention to provide adamper assembly which absorbs energy and interferes with and thusminimizes or eliminates unwanted harmonic vibration of an associatedmechanical element.

Further aspects, advantages and areas of applicability will becomeapparent from the description provided herein. It should be understoodthat the description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of the presentdisclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a perspective view of a transmission fill tube having a firstembodiment of a sleeve damper assembly according to the presentinvention installed thereon;

FIG. 2 is an enlarged, fragmentary, perspective view of a firstembodiment of a sleeve damper assembly according to the presentinvention on a transmission fill tube;

FIG. 3 is a perspective view of a transmission fill tube having a secondembodiment of a sleeve damper assembly according to the presentinvention installed thereon; and

FIG. 4 is an enlarged, fragmentary, perspective view of a secondembodiment of a sleeve damper assembly according to the presentinvention on a transmission fill tube.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

With reference to FIG. 1, a transmission fill tube upon which a sleevedamper assembly according to the present invention is mounted isillustrated and generally designated by the reference number 10. Thetransmission fill tube 10 is typically an elongate, hollow tube that issecured to and extends upwardly from a transmission housing 12. Thetransmission housing 12 receives, locates and protects variouscomponents (not illustrated) of the transmission 14. The transmissionfill tube 10 is typically between one foot and four feet in length (30.5cm. to 122 cm.) in a typical passenger car, light truck or sport utilityvehicle and extends from the transmission housing 12 upwardly to alocation of convenient access within the engine compartment to aterminus 16. Depending upon the length of the transmission fill tube 10,it may include one or more brackets or straps 18 which are secured orattached to the transmission housing 12 and/or an engine 20 by, forexample, suitable fasteners such as bolts or machine screws 22. Thetransmission fill tube 12 facilitates addition of transmission fluid(not illustrated) to the transmission 14 as needed. In addition tofacilitating addition of fluid to the transmission 14, the transmissionfill tube 10 receives a removable flexible, typically flat shaft ordipstick 24 that facilitates determining the level of fluid in thetransmission 14. The dipstick 24 preferably includes a top seal, cap orgrommet 26 that closes off the terminus 16 of the transmission fill tube10.

A significant portion of the transmission fill tube 10, especially thatportion most distant from the transmission housing 12 and adjacent theterminus 16, may be unsupported. As noted above, such unsupportedlengths of a tubular, elongate component such as the transmission filltube 10 may permit or encourage resonance or sympathetic vibration ofthe component.

Referring now to FIGS. 1 and 2, a first embodiment of a sleeve damperassembly according to the present invention is illustrated and generallydesignated by the reference number 30. The sleeve damper assembly 30 istypically and preferably installed on an unsupported portion of thetransmission fill tube 10. The sleeve damper assembly 30 includes atubular damper sleeve 32 which defines a through, axial passageway 34.The damper sleeve 32 is preferably fabricated of conventional closedcell polyurethane foam satisfying ASTM D1056 2D2 and having a UL 94 V-Ocoating. Other relatively lightweight, softly resilient materials suchas foam rubber and materials having different densities are alsosuitable.

The damper sleeve 32 is preferably between about 3 inches (76.2 mm.) to6 inches (152.4 mm.) in length, preferably has a wall thickness ofbetween about 0.20 inches (5.1 mm.) and 0.35 inches (9.0 mm.) andpreferably an inside diameter (the diameter of the axial passageway 34)of between 0.75 inches (19.05 mm.) and 1.25 inches (31.75 mm.).Preferably, as well, the outside diameter of the transmission fill tube10 will be at least one-half of the diameter of the axial passageway 34.The foregoing dimensions are approximate only and it should beunderstood that they will vary (even outside the stated ranges)depending upon the density of the material of which the damper sleeve 32is fabricated, the outside diameter of the transmission fill tube 10,the particular frequency or band of frequencies desired to be attenuatedby the sleeve damper assembly 30 and other design variables.

Below the damper sleeve 32 and disposed in supporting relationship withit is a fixed collar, stop or support 36. The collar, stop or support 36has an outer diameter that is slightly larger than the diameter of theaxial passageway 34 such that the damper sleeve 32 cannot slide along ordown the transmission fill tube 10 beyond the location at which theupper edge of the collar, stop or support 36 engages the lower edge ofthe damper sleeve 32. The stop or support 36 may be of any suitablematerial such as the closed cell foam described above or otherreasonably durable and lightweight material. If fabricated of closedcell foam or other, similar resilient material, the stop or support 36may be readily secured to the transmission fill tube 10 by, for example,a strap, cable tie 38 or a similar tensioning device. Alternatively, asuitable adhesive may be utilized.

Referring now to FIG. 3, a second embodiment of a sleeve damper assemblyaccording to the present invention is illustrated and generallydesignated by the reference number 50. The second embodiment of thesleeve damper assembly 50 is shown in place on a transmission fill tube10′. The transmission fill tube 10′ extends from a transmission housing12′ and may include one or more mounting brackets or straps 18′.Typically, the transmission fill tube 10′ receives a removable flexible,typically flat shaft or dipstick 24′ that facilitates determining thelevel of fluid in the transmission 14. The dipstick 24 preferablyincludes a top seal, cap or grommet 26′ that closes off the fill tube10′. Proximate the upper terminus 16′ of the transmission fill tube 10′,typically in an unsupported region, is disposed the sleeve damperassembly 50. The sleeve damper assembly 50 includes a single, elongatetubular damper sleeve 52 which defines a through, axial passageway 54.The damper sleeve 52 is preferably fabricated of conventional closedcell polyurethane foam satisfying ASTM D1056 2D2 and having a UL 94 V-0coating. Other softly resilient materials such as foam rubber andmaterials having different densities are also suitable.

The damper sleeve 52 is preferably between about 4 inches (101.6 mm.) to7 inches (177.8 mm.) in length, preferably has a wall thickness ofbetween about 0.20 inches (5.1 mm.) and 0.35 inches (9.0 mm.) andpreferably an inside diameter (the diameter of the axial passageway 54)of between 0.75 inches (19.05 mm.) and 1.25 inches (31.75 mm.).Preferably, as well, the outside diameter of the transmission fill tube10′ will be at least one-half of the diameter of the axial passageway54. The foregoing dimensions are approximate only and it should beunderstood that they will vary (even outside the stated ranges)depending upon the density of the material of which the damper sleeve 52is fabricated, the outside diameter of the transmission fill tube 10′,the particular frequency or band of frequencies desired to be attenuatedby the sleeve damper assembly 50 and other design variables.

Referring now to FIGS. 3 and 4, the damper sleeve 52 includes a pair ofradially aligned, that is, diametrically opposed, axially extending cutsor slits 56A and 56B at the lower end of the damper sleeve 52, that is,the end most distant from the terminus 16′ of the transmission fill tube10′. The damper sleeve 52 is preferably disposed on the transmissionfill tube 10′ with the cuts or slits 56A and 56B aligned horizontally.Threaded through the cuts or slits 56A and 56B, around the lower half ofthe transmission fill tube 10′ and over the upper, outside surface ofthe damper sleeve 52 is a strap or cable tie 58 or similar tensioning orsecurement device. Positioning the strap or cable tie 58 proximate oneend of the damper sleeve 52 (the lower end) allows a maximum length ofthe damper sleeve 52 to move and vibrate to interfere with and cancelout vibrations and to absorb energy. Fastening the cable tie 58 aroundthe lower half of the transmission fill tube 10′ and the upper surfaceof the damper sleeve 52 maintains an open region 62 within and at thelower portion of the axial passageway 54 to allow dirt and debris topass through the damper sleeve 52 and thereby prevent the accumulationof dirt and debris within the axial passageway 54 of the damper sleeve52 which would interfere with its operation.

In operation, both the first embodiment of the sleeve damper assembly 30and the second embodiment of the sleeve damper assembly 50 function inessentially the same way: as untuned, i.e., chaotic, dampers or energyabsorbing and dissipating devices to damp unwanted resonances orsympathetic vibrations in unsupported portions of linear elements suchas cables, and engine and transmission fill tubes in motor vehicles.Thus, they be readily and easily fitted about and secured to suchelements and, without extensive tuning and matching of source and damperfundamental and harmonic frequencies, they function as untuned, chaoticdampers to attenuate the motion of the linear element and to absorb anddissipate vibratory energy over a broad frequency spectrum.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

What is claimed is:
 1. A sleeve damper assembly for reducing resonanceof a linear element of a motor vehicle comprising, in combination, anelongate tubular damper sleeve fabricated of plastic foam and definingan axial through passageway adapted to receive a linear element, and aretaining collar having an outside diameter larger than a diameter ofsaid through passageway, said retaining collar secured to said linearelement adjacent said damper sleeve.
 2. The sleeve damper assembly ofclaim 1 wherein said axial through passageway has a diameter larger thanan outside diameter of said linear element.
 3. The sleeve damperassembly of claim 1 wherein said linear element is a transmission filltube.
 4. The sleeve damper assembly of claim 1 wherein said tubulardamper sleeve has a length of seven inches or less.
 5. The sleeve damperassembly of claim 1 wherein said plastic foam is closed cellpolyurethane.
 6. The sleeve damper assembly of claim 1 wherein saidretaining collar is secured to said linear element by a strap.
 7. Thevibration damper assembly of claim 1 wherein said tubular sleeve andsaid retaining collar are distinct components.
 8. A random, chaoticdamper assembly for reducing resonance of a non-rotating linear elementof a motor vehicle comprising, in combination, an elongate circulardamper sleeve fabricated of plastic foam and defining an axial throughpassageway adapted to receive a linear element, and a retaining collarhaving an outside diameter larger than a diameter of said throughpassageway, and means for securing said retaining collar to said linearelement.
 9. The chaotic damper assembly of claim 8 wherein said axialthrough passageway of said circular damper sleeve has a diameter largerthan a diameter of said linear element.
 10. The chaotic damper assemblyof claim 8 wherein said linear element is a transmission fill tube. 11.The chaotic damper assembly of claim 8 wherein said linear element is anengine dipstick tube.
 12. The chaotic damper assembly of claim 8 whereinsaid circular damper sleeve has a length of seven inches or less. 13.The chaotic damper assembly of claim 8 wherein said plastic foam isclosed cell polyurethane.
 14. The chaotic damper assembly of claim 8wherein said means for securing said retaining collar to said linearelement is one of a strap, a cable tie and adhesive.
 15. A sleeve damperassembly for reducing resonance of a transmission fill tube of a motorvehicle comprising, in combination, an elongate tubular damper sleevefabricated of plastic foam and defining an axial through passagewayadapted to receive said transmission fill tube, and a retaining collarhaving an outside diameter larger than a diameter of said throughpassageway, and a strap for securing said retaining collar to saidtransmission fill tube adjacent said tubular damper sleeve.
 16. Thesleeve damper assembly of claim 15 wherein said tubular damper sleevehas a length of seven inches or less.
 17. The sleeve damper assembly ofclaim 15 wherein said plastic foam is closed cell polyurethane.
 18. Thesleeve damper assembly of claim 15 wherein said tubular damper sleeveand said retaining collar are fabricated of closed cell foam.